高动态X射线多谱CT成像理论与方法研究

项目名称： 高动态X射线多谱CT成像理论与方法研究

项目编号： No.61471325

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 赵英亮

作者单位： 中北大学

项目金额： 86万元

中文摘要： 在现有CT系统中，常规固定能量的三维CT成像方法，对于厚薄差异大的工业复杂结构件，因成像系统动态范围受限，易出现过曝光和欠曝光共存现象，导致图像重建质量欠佳。另一方面，X射线多谱成像相对于单能谱成像，其能谱信息更丰富，可依据能谱与衰减系数的多谱对应性，实现检测对象微观信息的定性与定量检测。而在多谱成像中，光子计数型探测器具有独特的优势，可直接在数据接收端实现能谱分离与解析，但是由于价格昂贵、承受能量峰值小、分离能级受限等，无法满足复杂结构多谱CT成像的工程需求。因此针对该问题，项目结合检测对象的预扫描信息，研究能量预测与反馈微调、能谱分离与能谱优化、投影信息的优化获取、递变能量多谱CT重建，以及能谱评估与补偿理论，探索新的数据采集策略和CT重建算法，实现复杂异形工件的高动态多谱CT成像，在不改变现有设备硬件条件的基础上，进一步提高现有射线CT检测系统的精度。

中文关键词： 多谱三维CT；射线无损检测；能量递变；图像重建

英文摘要： In traditional CT system, for the greatly different thickness of workpieces, three-dimensional CT imaging method of single dose is largely limited in dynamic range. And it causes to the coexistence of over-exposure and underexposure so to result in poor quality image reconstruction. On the other hand, respected to the single spectral imaging, multi-spectral imaging is of richer spectrum of information, and can use the multispectral correspondence between energy spectrum and attenuation coefficient, to further achieve qualitative and quantitative detection on microscopic information of detected objects. In the multi- spectral imaging, photon counting detectors has unique advantage that spectrum separation and analysis can be directly achieved in the data receiving end. But due to more expensive price, smaller energy peak resistance and limited separation energy level, etc., it cannot meet the engineering needs for multi-spectral CT imaging of complex structural objects. Therefore, aiming at the problem, combined with the pre-scan information, studying the energy forecasting, feedback to fine-tune, spectrum separation, spectrum optimization, improved access to projection information, graded multi-spectral energy CT reconstruction, energy spectrum evaluation and compensation theory, the project explores a new strategies of data collection and CT reconstruction algorithms to achieve the high dynamic multi-spectral CT imaging of complex shaped workpieces, and It can greatly improve the accuracy of CT -ray inspection systems in the existing equipment.

英文关键词： multispectral 3D CT;X-ray NDT;energy graded;image reconstruction